This invention relates to a method for motion encoding of tissue structures in ultrasonic imaging for the investigation of living bodies. More specifically, the invention relates to the field of ultrasound diagnosis of the cardiovascular system, particularly methods for measuring and visualizing tissue wall movement and wall structure based on time dependent 2D or volumetric ultrasound acquisition.
The terms tissue structures, tissue walls, interfaces or boundaries are used to designate more or less the same object throughout the present description.
Techniques for acquiring 2D, 3D and 4D ultrasonic studies are known as described, for example, in Tomtech Systems Inc., Echoscan User Manual, USA 1993. Visualization techniques like surface shading, depth shading, max/min rendering, average rendering, surface texturing and transparency models are also known, as described in R. A. Drebin, L. Carpenter, and P. Hanrahan, "Volume rendering" Computer graphics, 22(1):65, 74, August 1988; M. Levoy, "Volume rendering: Display of surfaces from volume data" IEEE Computer Graphics and Applications, pages 29-37, May 1988; Hans-Peter Meinzer, Kirsten Meetz, et al., "The Heidelberg raytracing model", IEEE Computer Graphics and Applications, pages 34-43, November 1991; Bj.o slashed.rn Olstad, "Maximizing image variance in rendering of columetric data sets", Journal of Electronic Imaging, 1:245-265, July 1992B.o slashed.rn Olstad and Nils Thune, "Visualizing 1-d medical ultrasound data" Proceedings IEEE Visualization '91, San Diego, Calif., October 1991; and P. Sabella, "A rendering algorithm for visualizing 3d scalar fields", Computer Graphics, 22(4):51-55, August 1988.
The invention relates to a combination of surface detection in ultrasonic imaging and transparent rendering through the usage of the distance transform. The distance transform is discussed in G. Borgefors, "Centres of maximal discs in the 5-7-11 distance transform", Proc. of the 8th SCIA, Troms.o slashed., 1993; and G. Borgefors, "Distance transformations in digital images", Computer vision, graphics and image processing 34, 1986, pp. 344-371.
Wall motion encoding has earlier been described in multi-slice ultrasonic imaging J.o slashed.rgen M.ae butted.le et al. "Three-Dimensional Echocardiography for quantitative left Ventricular Wall Motion Analysis: A Method for Reconstruction of Endocardial Surface and Evaluation of regional Disfunction" Echocardiography 1994-11,4 page 397-408; Knut Bj.o slashed.rnstad et al. "Quantitative Computerized Analysis of Left Ventricular Wall Motion"Computerized Echocardiography. Pezzano 1993, page 41-55.